


Test

by NihilismPastry



Category: Undertale (Video Game)
Genre: Alternate Universe - Swapfell, BDSM, Biting, Blood Kink, Bondage, Dirty Talk, Ecto-dick, F/M, Female Reader, Marking, Master/Pet, Power Bottom, blindfold
Language: English
Status: Completed
Published: 2016-11-11
Updated: 2016-11-11
Packaged: 2018-08-30 05:29:47
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,291
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8520292
Author URL: https://archiveofourown.org/users/NihilismPastry/pseuds/NihilismPastry
Summary: Sans wants to test his willpower.





	

**Author's Note:**

> A request from Silcatian.
> 
> Silcatian: If you still have a need for Swapfell how about SF!Sans as a power bottom? Having the reader blindfold and tie him up in his sleep, seeing how much he can take before the malicious Sans is a begging, panting, moaning mess? Maybe have a male reader if you feel like it. ;)
> 
> One thing to note, is that I doubt a human could get the jump on the Captain of the Royal Gaurd, in a world where he expects to die at any moment. So no, this didn't happen in his sleep.

You tightened the rope around his thin wrists, a frown pulled on your lips. "Are you sure about this, Sans? I've never done this before..."

"I WILL STILL BE IN CHARGE, PUP." He said. "YOU'LL JUST HAVE ME BOUND AND WILL DO AS I SAY. IT'S A TEST OF WILL! ALPHYS SAID I SHOULD BE READY FOR ANY SITUATION, AND THAT YOU HAVE TO HONE YOUR PATIENCE."

You released the old, cum stained rope and sat back on your heels, looking down at your skeleton lover. His wrists were tied above his head, a blindfold over his sockets, and his clothes taken off. There was already a hint of blue in his cheeks, but he didn't actually seem embarrassed outside of that. He had his usual slasher smile, and looked raring to go. You plucked up a violet collar from the floor, and buckled it to your throat. It was simple, just purple leather with a gold clasp, and Sans's insignia carved in the front.

Once it was on, you crawled over to him, and hovered over his outstretched form. "Master, what would you like me to do first?"

As soon as the words left your mouth, a flurry of pale blue sparks collected at his pelvis, before a girthy cock appeared. "Lick it."

You leaned down and let your tongue slide against the magic. It tasted almost like raspberries, and had a cold temperature. You dragged your tongue up to the tip, and swirled around it, earning g a low growl from the monster. You paused in your task, and glanced back up to the skeleton's face. The blue in his cheeks was darker, and he was grinding his fangs together. When he noticed you stopped, he pumped his hips. "I DIDN'T TELL YOU TO STOP, BITCH. KEEP SUCKING."

You did as you were told, closing your mouth around the hard cock. Your gave a hard suck, and heard the skeleton growl out profanities. You continued your task, using your mouth and hand to bring your lover higher. This was very different than what you were used to. Sex with Sans usually meant you were the one bound and gagged, begging to be released so you could touch him. Though, Sans always loved to try something new either in or outside the bedroom. He was a tenacious monster, and jumped to spread his horizons any chance he got. 

You, on the other hand, wasn't so eager. Heck, even falling for your soul mate had been an uphill battle. When you first met Sans, you had been terrified of him. Falling into the Underground, and meeting creatures ripped out of your nightmares had made you into an anxiety ridden mess. And even with the cheerful skeleton always clinging to you and being his version of nice, it had been a leap out of your comfort zone to even hold his hand with prompting.

My how far you had come.

A strangled moan pulled you out of your thoughts, and that was your only warning as cold cum burst into your mouth. It didn't actually taste like anything, and as you swallowed you had to be careful due to how thick it was. You pulled away from his member with a lewd pop, some of the cum tricking down the side of your mouth. Sans's mouth was open wide, and his tongue could be seen inside his mouth. "KISS ME."

You pressed your lips to his fangs, and he thrust his tongue into your mouth. You shut your eyes and moaned, pressing deeper into the kiss. Sans growled into your mouth, and you heard the familiar sound of rope straining. Your eyes fluttered open, and your suspicions were confirmed. Sans was pulling at the rope, trying to get to you and fully control the situation. "Do you want me to untie the ropes, Master?"

His phalanges clenched and unclenched, the light clicking of bone against bone mixed with his growls. You opened your mouth to repeat the question, but he shook his head. "NO, I TOLD ALPHYS I CAN CONTROL ANY SITUATION! I CAN DO THIS TOO!"

"If that's what you want, Master." 

 "IT IS!" He twisted in his bonds again. "I WOULD ALSO LIKE TO YOU BOUNCE YOURSELF ON MY COCK."

 You crawled over to his waist, and hovered over his cock. You grabbed his base, and carefully pushed yourself down on his girthy member. You moaned and gripped him tighter, prompting a growl from the monster. Once you were fully seated on his lap, you glanced up to him, looking for permission. He nodded, and you slowly lifted yourself up,until just his tip was inside you, before dropping yourself back down.

You weren't used to this slow pace, even with Sans helping you along, it still didn't seems fast or hard enough. Sans seemed to agree as well, his hips desperately rising to meet your own. "C-COME HERE, I NEED TO MARK YOU. YOUR BLOOD NEEDS TO BE ALL OVER US."

Your gripped his ribs and hunched over, pressing your neck to his his fangs. There was a dull snap,and your felt the cool pop of his tongue on your neck. You shut your eyes, and stiffened when you felt his fangs sink into your neck. It hurt like hell, and there was blood spilling down your body. It was warm, sticky, and made your body shudder. The skeleton released you with a blood smudged grin, his tongue lapping up the access on his face. "YOU'RE SO BEAUTIFUL LIKE THIS, PUP. EVEN WHEN I'M TIED UP YOU KNOW YOU'RE MINE."

He smashed his teeth to yours in a bruising kiss, fighting to pick up his pace. You gasped and arched your back when be hit your g-spot. You felt him grin into the kiss, and hit the spot again. Your walls clamped down on his dick, and you felt your orgasm rocket through your body. You screamed his name as he kept pounding into you, snarls ripping through the skeleton. Finally his hips stuttered, and you felt cold cum spurt into your body. You dragged against your lover, eyes shut, and a low sigh escaping you. "You lasted the whole time without breaking your bonds."

"YUP, JUST WAIT UNTIL ALPHYS HEAR'S." His eyes brightened up in excitement. " SHE MIGHT LET ME PERFORM THE EXECUTIONS THIS MONTH!"

"Y-yeah."

You heard the rope strain again, before you felt cold phalanges caress your back. Technically you were supposed to untie him, but you wouldn't rain on his parade. "YOU KNOW HUMAN, YOU OBEYED YOUR ORDERS PERFECTLY. YOU'RE SUCH A GOOD PUP."

 "Thank you, Master."

"BUT WHY DIDN'T YOU TRY TO TAKE CONTROL?" He asked. "I WAS AT MY MOST VULNERABLE. YOU COULD HAVE BROKEN MY SPINE AND WENT TO TERRORIZE THE REST OF SNOWDIN WITHOUT FEAR OF OPPOSITION. OR HAVE THAT DESSERT SEX."

"Vanilla," You said, before leaning up and pressing a kiss between his eyes. "and I love you too much to try to hurt you, or take advantage of you."

"EVEN THOUGH I YELL AT YOU?"

"Mhm."

"AND TAKE PICTURES OF YOU ALL THE TIME?"

"Yup."

"AND-"

"I love you up unconditionally." Your words were soft, as you stared down at him. "No matter what, I'll always love you, Sans."

He flushed a dark blue and looked away. "W-WELL, I THINK I LOVE YOU A LOT TOO. EVEN THOUGH YOU SNORE, AND CAN'T COOK, AND MAKE STUPID SKELETON PUNS."

You snorted, and did your best to hold in a laugh. "Thank you for being so gracious."

His arms squeezed you tighter to his ribs, and he nuzzled your cheek. "YOU'RE WELCOME. I LOVE YOU TOO MUCH TO GET RID OF YOU OVER SMALL THINGS. I'M GONNA KEEP YOU FOREVER."

**Author's Note:**

> Good grief this felt mediocre. But this was my first time writing a power bottom, and I had no idea what I was doing. XD
> 
> You know what does know what it's doing? My tumblr! http://nihilismpastry.tumblr.com


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